Design a FM tranmitter step by step (advanced questions)

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In summary, someone needs to provide a schematic for a basic FM transmitter before asking questions about components and parameters.
  • #1
yy.toh
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Guys, from circuitstoday.com I researched, I understood ig picture of a basic FM transmitter. there should have basic blocks like audio amp, modulator (oscillator included), radio amp and the anttena. suppose I want to build a FM transmitter, what is my first step?

step1
says I choose 0.5m long copper wire anttena, diameter to be determined, and want to have a tranmission length of 1m, what parameter is to be tuned at the anttena?can you provide the anttena formula as complete as you can-is it material dependent?how to caculate the power to be transmitted?

step 2
after I understodd the power to be transmitted, I may define the output power from radio amp, right?can someone tell me how to decide/calculate the capacitance of the ac decoupling?

step3
now come to the part of oscillator, says I use a LC osciallator the frequencies could be determined right?the connection of the LC oscillator, it should be connected before the node of ouput resistor of the transistor or after?how do we determine the value of the feedback capacitor connected to the osicillator

step4
about amplifier in general, based on what we determine the biasing resistor value, is it referring the amplifier spec for its specify Veb, Vcb?

great thanks...
and for sharing, designing a remote control is easy as just to combine the encoder/decoder with the trasceiver, so the key knowledge is to learn up the RF circuits and then the RC would be easy, just for sharing...

someone reply me please...
please...
 
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  • #2
yy.toh,

I think before the "advanced questions" can be addressed, you should probably reference the schematic you are referring to, for instance is it this one:

http://www.circuitstoday.com/medium-power-fm-transmitter-circuit

Toward the end of your post you make reference to a "remote control", is this the actual purpose of the device?

I do not have much experience with RF Transmitters/Receivers personally, but many here do; if you want help you will need to give them a specific schematic to look at before asking questions about components and parameters. What little experience I have with RF circuits is that very small details can have a large impact on performance. Additionally, defining the specific purpose of the circuit will go a long way to getting good advise.

Fish
 

1. What are the basic components needed to design an FM transmitter?

The basic components needed to design an FM transmitter include an oscillator circuit, a frequency modulator, a power amplifier, an antenna, and a power supply.

2. How do you select the appropriate frequency for an FM transmitter?

The frequency for an FM transmitter is typically selected based on regulations set by the governing body in your country. In the United States, for example, the FCC regulates the frequency range for FM radio broadcasting to be between 88 MHz and 108 MHz.

3. Can you explain the process of frequency modulation and how it differs from amplitude modulation?

Frequency modulation (FM) is a method of encoding information onto a carrier wave by varying the frequency of the wave. This results in a signal with a constant amplitude but varying frequency. Amplitude modulation (AM), on the other hand, encodes information by varying the amplitude of the carrier wave while keeping the frequency constant.

4. How do you ensure the stability and accuracy of an FM transmitter?

To ensure stability and accuracy, an FM transmitter must have a stable oscillator circuit that produces a constant and accurate frequency. This can be achieved by using high-quality components, proper shielding, and frequency stabilization techniques such as phase-locked loop (PLL) circuits.

5. Can you provide any tips for optimizing the range and sound quality of an FM transmitter?

To optimize the range and sound quality of an FM transmitter, it is important to have a well-designed antenna and a clean power supply. Additionally, proper tuning and calibration of the transmitter can also greatly improve performance. It is also important to consider any potential sources of interference and select a frequency that is not already being used in your area.

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